Log-barking drum and toothed element therefor



J l 5 1 55 C. A. THOMPso LOG-BARKING DRUM AND TOOTHED ELEMENT THEREFOR 3 Sheets-Sheet 1 Filed March 50, 11953 INVENTOR. Cfl/VE'Y 4. 72/oMPso/v J l 5 1955 c. A. THOMPSON 2,712,330 LOC-BARKING DRUM AND TOOTHED ELEMENT THEREFOR Filed March 30, 1953 3 Sheets-Sheet 2 INVENTOR.

BY 'A E 4. filoMpsaA July 5, 1955 THOMPSON 2,712,330

LOG-BARKING DRUM AND TOOTHED ELEMENT THEREFOR Filed March 30, 1955 3 Sheets-Sheet 3 INVENTOR. Cfl/VEY ,4. THOMPSON United States Patent 0 LOG-BARKWG DRUM AND TUOTHED ELEMENT THEREFOR Caney A. Thompson, Mebile, Ala., assignor to International Paper Company, New York, N. Y., a corporation of New York Application March 30, 1953, Serial No. 345,350 3 Claims. (Cl. 144-208) This invention relates to new and useful improvements in apparatus for removing the bark from log billets and particularly seeks to provide a drum type of log barker which includes a series of internally positioned, toothed elements to increase the efiiciency of such barkers, particularly when used on hardwood species.

The normal drum barker consists of a relatively large diameter, long, open-ended cylinder fabricated from a plurality of longitudinal stringers held together by a plurality of supporting annuli. Slots are provided between the longitudinal stringers through which the removed bark entire interior of the drum.

A further object of this invention is to provide a barking drum of the character stated in which the toothed elements may comprise a series of serratedly-arranged plates rigidly affixed along the entire interior of the drum.

A further object of this invention is to provide a bark- 2,712,330 Patented July 5, 1955 Fig. 10 is a vertical transverse section taken along line 10-10 of Fig. 9;

Fig. 11 is an enlarged fragmentary elevation taken within the zone 1111 of Fig. 9;

Fig. 12 is a vertical transverse section taken along line 1212 of Fig. 11;

Fig. 13 is a fragmentary development of the drum and shows a further modification of the positioning of the toothed elements therein;

Fig. '14 is a partly schematic left end elevation of the barking drum modified by the addition of a plurality of successively offset bar-supported lifting plates; and

Referring to the drawings in detail, this invention as llustrated is embodied in a two-section cylindrical barkmg drum generally indicated at 5, each section of which plates 13 rigidly affixed to the segments 12 and to the The inner edges of the segments 12 are provided with a continuous series of generally sharp, pointed triangularly-shaped teeth 14.

By the provision of the internally toothed annular elements l1 operation of the drum for the debarking of the pulpwood billets will be efiected in the normal manner by simple rotation of the drum through the driving connections 8 and 9. However, as the billets are fed into the receiving end of the drum and a small pile thereof accumulates and gets tumbled over and over as the result of the rotation of the drum the uppermost billets of the pile progressively will fall down and contact the toothed surfaces of the annular elements 11 and the teeth 14 thereof will penetrate the bark on the billet to facilitate its removal as the tumbling action continues. it may be noted at this point that most barking drums used today are designed to operate upon pulpwood billets having a length of 4 feet. Accordingly, the spacing between adjacent annular elements 11 should be slightly less than the length of the pulpwood billets in order to assure successful and multiple contacts of each billet with the teeth 14 as the billet progresses through the drum.

In Figs. 7 through 12 of the drawings there is illusrated a barking drum containing a modified type of internally disposed toothed structure. The purpose of this is the same as that heretofore described in connection with the annular elements 11, but by use of this modified form it is possible to construct the barking drum as a shell formed from plate iron or steel rather than fabricating the drum from a plurality of longitudinal stringers held in cylindriform arrangement by the externally positioned mounting rings 7.

Fig. 7 of the drawings discloses a development of the interior surface of a ing the modified toothed elements with the drum axis corresponding to that of Fig. l. In this form the plating of the shell of the drum is indicated at 15, and it will be seen that the internally positioned toothed elements comprise a plurality of rows it, each of which is formed from a plurality of toothed elements 17 arranged in a serrated or zigzag manner. The lower apex between each pair of elements 17 is filled by a reinforcing plate assembly 18, and immediately thereabove as viewed in Fig. 7 and 9 the shell is slotted as at 19 to provide an aperture through which the free bark may drop during the course of debarking operations. In this form of barking drum the teeth of the element 17 may be shaped the same as the teeth 14 of the arcuate segments 12 or preferably they should be contoured as indicated in the enlarged fragmentary view shown in Fig. ll which may be described as somewhat chisel-shaped in that the leading edge 26 terminates in a sharp corner 21 and the tooth then exhibits a downwardly and rearwardly slanted fiat portion 22 and a trailing edge 23. This shape of tooth is particularly advantageous in connection with the removal of bark from hardwood species in which the actual thickness of bark is substantially less than that normally appearing on softwood species. With this form of tooth whenever a pulpwood billet falls from the tumbling pile onto the toothed elements 17 the sharp corner 21 will penetrate the bark, but the flat, rearwardly slanting portion 22 of the tooth will prevent penetration greater than the thickness of the bark. In this manner the bark can properly be removed without any unnecessary splintering or brooming of the underlying wood.

Again, in this form of toothed elements lateral bending thereof may be prevented through the use of gusset plates 24 rigidly aflixed to the elements 17 and to the adjacent shell 15'.

In Fig. 13 there is illustrated a further modification of barking drum which may be fabricated either in the general form illustrated in Fig. l or the modified form as indicated in the development of Fig. 7. The present modification as illustrated in the fragmentary development of a barking drum shown in Fig. 13 provides for a continual helix of toothed elements in the drum. In this form the drum shell is indicated at 25 and the toothed portion of a barking drum containelements at 26 and the axis of the drum corresponds to that of Fig. 1. In this case also the pitch of the helix should be slightly less than the length of the pulpwood billets to be operated upon in order to assure multiple contacts of each billet with the toothed elements 26 during its passage through the drum.

In connection with the debarking of certain hardwood species where the bond between the bark and the underlying wood is particularly tight, it may be found necessary to augment even the supplementary barking action as effected by the above described toothed elements by the addition of lifting plates or paddles to accentuate the tumbling action of the pulpwood billets as the drum is rotated. To this end each section of the barking drum may be provided with a plurality of internally fastened, diametrically extending cross bars 27 spaced along the length of the drum as indicated in Fig. 15 with successive cross bars being angularly offset with respect to the adjacent cross bar by an angle preferably of 45. Each end of each cross bar is provided with a lifting or tumbling plate 2.8 fastened to the inner surface of the cylinder and to the lead face of the cross bar, i. e., that face in the direction of rotation.

It is, of course, to be understood that various details of arrangements and proportions of parts may be modified within the scope of the appended claims.

I claim:

1. In a barking drum wherein is provided an openended cylinder, means for rotatably supporting said cylinder and means for rotating said cylinder; the combination of a multiplicity of longitudinally extending rows of arcuate toothed elements rigidly affixed to the interior of said cylinder in positions to be contacted by individual wood billets as the result of tumbling action induced by rotation of said drum, the toothed elements of each of said rows comprising a multiplicity of individual toothed elements arranged zigzaggedly, each tooth of said toothed elements when viewed from one side thereof including a leading edge extending substantially radially with respect to the axis of rotation of the drum and terminating in a sharp inner corner, a trailing edge spaced from said leading edge, and a flat surface extending between said sharp inner corner and said trailing edge, said flat surface sloping outwardly towards the periphery of said drum.

2. A barking drum in accordance with claim 1 in which the cylinder is provided with a plurality of diametrically positioned cross bars rigidly affixed therein along the length thereof, each successive cross bar being angularly offset with respect to the adjacent cross bar and being provided at each end with a lifting plate rigidly secured thereto and to the adjacent face of the associated cylinder.

3. A toothed element for a barking drum comprising an arcuate plate provided along its inner concave edge with a multiplicity of bark-engaging teeth, each of which when viewed from one side of said plate includes a leading edge extending substantially radially with respect to the axis of curvature of said arcuate plate and terminates in a sharp inner corner, a trailing edge spaced from said leading edge, and a fiat inner surface extending between said sharp inner corner and said trailing edge, said flat inner surface sloping chordally from said sharp inner corner towards the proximate portion of the periphery of curvature of said arcuate plate.

References Cited in the file of this patent UNITED STATES PATENTS 

